code: def _read(self, file_path: str):
      for i in range(10):
          source = f"Hi there, I'm the {i}th instance"
          target = f"Hello, {i}th instance!"
          yield self.text_to_instance(source, target)
  
imports: from typing import List, Iterable, Dict
  import torch
  import pytest
  from allennlp.common.testing import requires_gpu
  from allennlp.data.instance import Instance
  from allennlp.data.dataset_readers import DatasetReader
  from allennlp.data.data_loaders import MultiProcessDataLoader, WorkerError
  from allennlp.data.fields import Field, TextField, MetadataField, TensorField
  from allennlp.data.tokenizers import PretrainedTransformerTokenizer
  from allennlp.data.token_indexers import PretrainedTransformerIndexer
  from allennlp.data.vocabulary import Vocabulary
  from allennlp.data.data_loaders.data_collator import LanguageModelingDataCollator
label_desc: Use image node_id 2 for calling the MockOldDatasetReader obj's underlying member method code with example usage: obj._read(file_path) without return types